State-educated students may get less help with university applications, struggle to find experiences to write about and are more likely to make mistakes, research suggests.

A study commissioned by the Sutton Trust claims that teenagers educated in the state sector are at a disadvantage when writing their personal statements to send to universities. It suggests that the current system favours private school pupils, who receive help to submit "carefully crafted" applications that contain details of numerous top work placements and after-school activities.

Dr Steven Jones of Manchester University looked at the personal statements of just over 300 would-be students, all with the same grades, from a mixture of private, comprehensive and grammar schools, and sixth form colleges.

Students applying to a UK university complete a personal statement giving details of their work experience, extra-curricular activities and any other information they believe would be relevant to their application.

Ucas has said that the statement is a way for a potential student to "stand out from the crowd". But Dr Jones' study claims that the statement in its current form may be unfair to those from lower or middle income homes.

The findings suggest that private school students are more likely to list a higher number of work-related experiences, and these could include stints working in places such as banks, law firms or leading businesses.

State school pupils listed a slightly fewer number of work placements, and these were more likely to include Saturday jobs and visits to businesses arranged by the school. The report also said that writing errors were three times more common in personal statements written by applicants at sixth form colleges than those from independent schools.

It noted that the personal statement was often said to make the university applications process fairer. "This research challenges that assumption, finding that independent school applicants are more likely to submit statements that are carefully crafted, written in an academically appropriate way, and filled with high status, relevant activities," it said.

Sutton Trust chairman Sir Peter Lampl said: "Personal statements should be more than an excuse to highlight past advantages. Applicants should outline how they might contribute to campus life, and universities should make it clear that applicants are not penalised for lacking opportunities in the past due to family circumstances."

Ucas chief executive Mary Curnock Cook, said: "The personal statement is one of a number of pieces of evidence that admissions staff look at when assessing an applicant's potential to succeed in higher education."